Audio/Video Glossary

RANDOM ERASE: Part of the UDF 1.5 specification. Random erase describes the ability to erase one file at a time from a CD-RW disc, just as you would on a hard disk. (See Sequential Erase
RASTER: The pattern of parallel horizontal scanning lines, traced by a video monitor’s electron beam, making up a video image.
RCA (connector): A type of connector used on all consumer VCRs and camcorders to carry the standard composite video and audio signals.
RC (Rewriteable Consumer) Time Code: A time code system, available on 8mm and Hi-8 tape formats only. The code can be added either before or after video recording without affecting the video or audio signals.
REAL TIME COUNTER: Any display showing tape length recorded (elapsed time) or remaining in an hours-minutes-seconds format.
RECORDABLE DISC: Media used in recordable CD systems. The blank disc is made of a bottom layer of polycarbonate, with a preformed track spiral which the recording laser follows when inscribing information onto the disc. This type of disc is therefore also called pre-grooved. A translucent layer of recordable material is laid on top of the polycarbonate, then a reflective layer of gold. On top there are thin layers of lacquer and label.
RED BOOK: (See CD-DA)
REDITHERING: The process of adding random data or noise to an analog audio signal for the purpose of moving data from the least-significant bits to the "higher" bits in a digital word. (See DITHER)
REGION CODING: A method by which DVD playback is restricted by geographic region. For example, DVDs and DVD players sold in the United States, Canada, and Mexico are usually coded for Region 1. A Region 2 disc from Japan will not play on a Region 1 player, unless that player has been specially modified to do so.
REMOTE SOCKET: A socket on a VCR or video camera which when connected, permits remote control of the unit. Remotes may be wired or wireless (infrared) and allow such control as play, pause, record, fast forward and rewind. (See CONTROL-S)
REPLICATION: Making multiple copies of a compact disc with a machine press.
REQUANTIZING DISTORTION: Distortion caused by shortening the word length of a digital audio sample as a result of truncation. Distortion occurs because the intervals at which the waveform are quantized become larger, changing the original waveform.
RESOLUTION: A measure of the ability to reproduce video detail. Generally, referred to as horizontal resolution and evaluated by establishing the number of horizontal lines which are clearly discernible on a test pattern. Resolution specifications are not very well standardized, especially as stated in connection with monitors. Using the rule of thumb of 80 lines per MHz of bandwidth, the VHS and 8mm tape formats typically achieve 240 lines of resolution, S-VHS and Hi-8 achieve 400, and broadcast achieves about 330. (See DEFINITION)
RF (Radio Frequency): A term used to describe the radio frequency signal band of the electromagnetic spectrum (about 3 MHz to 300 GHz). RF is used to carry modulated television signals and RF I/O connectors for cable TV and antennas, can be found on the back of most monitors and VCRs.
RF DISTRIBUTION: The process of supplying an RF signal to several devices simultaneously.
RF MODULATION: The process of combining a video signal with an RF source so the result can be transmitted to a television or VCR.
RGB (Red/Green/Blue): The raw basic Red, Green and Blue signal components of a color video signal source such as a camera or computer video board. Each of these include luminance information so that if you view them separately, you will see a shade of B/W image (I am ignoring the need for sync at the moment). Using a color encoder, in conjunction with sync information, a complete composite video signal comprising luminance and chrominance can be generated.
Each component of an RGB signal uses a lot of bandwidth which is why the YIQ and YUV matrixed signal formats were developed for NTSC and PAL video systems respectively. (See COMPOSITE VIDEO and COMPONENT VIDEO)
RS-232/RS-422: Computer communication standards used in video for the control of certain video equipment. Computer controlled VCRs, edit controllers, switchers and other studio equipment can commonly be found in professional video studios. Successfully linking two devices, at the very least, requires that they use the same communication protocol.
RSDL (Reverse Spiral Dual Layer): A technique by which a movie is split across two layers of a single DVD disc and is joined together for continuous playback. Allows longer movies (or movies with extra content) to be shown uninterrupted on a single side of a disc.

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